Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 172031
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
331 PM EST Fri Nov 17 2017

.SYNOPSIS...
High pressure will prevail through Saturday with a mainly dry
cold front passing through Saturday night into Sunday morning.
High pressure will then return through much of next week, although
at least one low pressure system could affect the area mid to
late next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
This Evening and Tonight: A mid/upper lvl low will push further off
the Northeast coast, helping maintain a northwesterly flow aloft
over the Southeast United States. At the sfc, high pressure centered
over the Mid-Atlantic states will shift offshore tonight, allowing
light northeast winds to become more southerly overnight. Given the
setup, dry conditions will persist through the night while winds
decouple under favorable radiational cooling conditions. However,
the light onshore wind along with a few clouds attempting to drift
onshore late will help keep temps warmer tonight than the previous
night. In general, lows should dip into the lower/middle 40s inland
and upper 40s/lower 50s near the coast.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Pretty good model agreement this period leads to high forecast
confidence. High pressure will be giving way to an approaching cold
front Saturday but increasing southerly winds will bring warmer
temperatures. The front is expected to move through Saturday night
into Sunday morning but limited moisture will only bring small rain
chances to the area. Cooler temperatures will move in behind the
front Sunday into Monday and could be cold enough /mid 30s/ Monday
morning for some frost across inland areas. Can`t even completely
rule out freezing temperatures in the normally colder inland rural
spots, mainly toward the CSRA/Midlands where winds should be less.

Lake Winds...Winds will increase on Lake Moultrie Saturday night
into Sunday as a cold front passes through the area, possibly
reaching marginal Advisory levels.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Dry high pressure is expected to prevail much of next week but
a Gulf surface low could lift northeast late in the week and
potentially bring some precipitation.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions are expected to prevail through 18z Saturday.

Extended Aviation Outlook: Brief/minor restrictions possible
Saturday night into Sunday morning due to low clouds/showers
with a passing cold front. Breezy/gusty conditions over 20 knots
at times Saturday afternoon through Sunday afternoon.

&&

.MARINE...
This Evening and Tonight: A northeast oriented pressure gradient
within a high pressure regime will help drive northeast winds
around 15 kt and seas as high as 3-5 ft early, but conditions
should steadily improve through the evening as the main center
of high pressure to our north reaches the Mid-Atlantic coast.
Overnight, the pressure gradient will begin to relax as the
center of high pressure to our north shifts off the Mid-Atlantic
coast. The pattern change will eventually turn winds from
northeast to southeast overnight. In general, winds will diminish
to 5-10 kt after midnight while seas range between 2-4 ft.

Saturday through Wednesday: Conditions will go downhill Saturday as
the pressure gradient tightens ahead of an approaching cold front
but should stay below Advisory levels until Saturday night when the
front passes. Best chances appear to be across the SC waters outside
Charleston Harbor and across the GA offshore waters. Conditions will
then improve later Sunday with some deterioration again toward mid
week when another cold front is expected to move through Tuesday
night, although no Advisories are anticipated at this time.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$
NEAR TERM...DPB
SHORT TERM...RJB
LONG TERM...JRL
AVIATION...DPB/RJB
MARINE...DPB/RJB



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